In steam generating systems, boiler water systems, steam lines, steam condensate lines, and the like, hereinafter referred to as boiler-steam condensate systems, one objective of a water treatment program is the removal of dissolved oxygen from the feedwater. The removal may be partially accomplished by using either Vacuum or thermal deaeration techniques or both. However, since complete oxygen removal cannot be effected by these techniques, further removal through the use of chemical oxygen scavenging agents has been a customary practice.
Sodium sulfite and hydrazine have commonly been used for scavenging oxygen in boilers, hot water plants, etc. However, the use of sodium sulfite introduces solids into the boiler water and hydrazine is a suspect carcinogen. In addition, these chemicals are not volatile and therefore are not effective in scavenging oxygen in steam and steam condensate lines.
Hydroxylamines and certain derivatives thereof are not only effective oxygen scavengers, but are also volatile, and have been used to control corrosion of iron and steel surfaces in boiler apparatus caused by dissolved oxygen. However, in boiler-steam condensate systems, there exist not only high temperature areas such as the boiler proper and steam lines but also low temperature areas such as boiler feedwater lines. The use of hydroxylamines has not been entirely effective for treating all areas of boiler-steam condensate systems.